From cd72a3fa412a5d1f7ee69977105de823c9db0d4b Mon Sep 17 00:00:00 2001
From: brutisso <unknown>
Date: Fri, 29 Apr 2011 09:11:03 +0200
Subject: [PATCH] 7040068: CMS: Possibly unsafe initialization of
 BlockOffsetArrayUseUnallocatedBlock Summary:
 BlockOffsetArrayUseUnallocatedBlock was intended to be turned off as part of
 BUG 6948538 but a code line in collectorPolicy.cpp actually kept it turned
 on. Reviewed-by: jwilhelm, ysr

---
 src/share/vm/memory/collectorPolicy.cpp | 2 --
 src/share/vm/runtime/globals.hpp        | 2 +-
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/share/vm/memory/collectorPolicy.cpp b/src/share/vm/memory/collectorPolicy.cpp
index 61efdd80f..7ad2bebaf 100644
--- a/src/share/vm/memory/collectorPolicy.cpp
+++ b/src/share/vm/memory/collectorPolicy.cpp
@@ -265,8 +265,6 @@ void TwoGenerationCollectorPolicy::initialize_flags() {
   MaxHeapSize = align_size_up(MaxHeapSize, max_alignment());
 
   always_do_update_barrier = UseConcMarkSweepGC;
-  BlockOffsetArrayUseUnallocatedBlock =
-      BlockOffsetArrayUseUnallocatedBlock || ParallelGCThreads > 0;
 
   // Check validity of heap flags
   assert(OldSize     % min_alignment() == 0, "old space alignment");
diff --git a/src/share/vm/runtime/globals.hpp b/src/share/vm/runtime/globals.hpp
index c16f88660..59f8fb95a 100644
--- a/src/share/vm/runtime/globals.hpp
+++ b/src/share/vm/runtime/globals.hpp
@@ -1824,7 +1824,7 @@ class CommandLineFlags {
   develop(bool, VerifyBlockOffsetArray, false,                              \
           "Do (expensive!) block offset array verification")                \
                                                                             \
-  product(bool, BlockOffsetArrayUseUnallocatedBlock, false,                 \
+  diagnostic(bool, BlockOffsetArrayUseUnallocatedBlock, false,              \
           "Maintain _unallocated_block in BlockOffsetArray"                 \
           " (currently applicable only to CMS collector)")                  \
                                                                             \
-- 
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